All,
I have a problem with grep/fgrep/egrep. Basically I am building a 200 times 200 correlation matrix. The entries of this matrix need to be retrieved from another very large matrix (~100G). I tried to use the grep/fgrep/egrep to locate each entry and put them into one file. It looks very slow with grep/egrep + reg exp. I am thinking that fgrep may will be faster, but not sure.
Does anyone have experience on this topic? or you may suggest some other commands/ways to solve this problem.
Regards,
Gary